Force-cup.



G. C. REEVES.

FORCE cuP.

APPLICATION FILED JULY 31, |912.

Patented Sept. 21, 1915.

GEORGE C. REEVES, OF CHICAGO, ILLTN'OIS.

FORCE-CUP.

Specification of Letters Patent.

Taten-teu sept. ai, Taio.

Application filed July 31, 1912. Serial No. 712,464.

To afl whom t may concern.'

Be it known that T, GEORGE C. REEVES, a

' citizen of the United States of America, and

a resident of Chicago, county of Cook, and

State of Illinois, have invented certain new and useful Improvements in Force-Cups, of which the following is a specification.

The main objects of this invention are to provide an improved form of force cup such as is used by plumbers for forcing obstructions through and from pipes; to increase the efiiciency of cupsof this kind and provide for accomplishing the desired results with the use of less material than is employed in the cups now in ordinary use; to increase the bending strength of the cup in a directionradially of the cup; and to permit greater circumferential elasticity of the cup with the same bending strength in a radial direction, than is permitted in other force cups now in common use.

An illustrative embodiment of this invention is shown in the accompanying drawings, in which Figure 1 is a bottom view of a fdrce cup constructed according to this invention. Fig. 2'is a vertical section of the device taken on the line A-A of Fig. 1.

In the construction shown in the drawings, the force cup comprises a concave elastic body 1 having its inner surface provided with the downwardly extending ribs 2 which are preferably uniformly spaced apart and are/preferably tapered at their lower ends 3 so as to terminate a considerable distance upward or inward of the rim or edge 4 of said concave body. This rim is preferably provided with an annular ridge or thickening 5. The body is provided with an upper tubular extension 6,y

the inner surface 7 of which is adapted to engage a handle in the usual way. In the specific form of cup shown in the drawings, which is known as a valve cup,'the extension or neck 6 is separated from the inner concave surface of the body by means of a wall 8. This wall is provided with the usual extension 9 through which a cut or slot 10 is v formed which connects the inner part of the extension 6 with the inner or body 1.

The inner part of the extension 6 is formed with a depression 11 into which the cut or slot 10 extends. In the construction shown part of the cup Yin the drawings the wall 8 is thickened at l2 below the depression 11. The cut or slot 10 and walls thereof form the usual air valve` used in devices of this kind. This cut or slot is exaggerated in size in Fig. 1. The walls of this slot normally lie close together.

, When pressure is exerted downwardly on the extension 6, and the lower edge 4L of the cup bears against a surface with which it may have an air-tight contact, the air pressure within the cup closes the valve in the usual way. When the downward pressure on the extension 6lis released the cup resumes its normal form, and the air is sucked into the cup through the depression 1l and the slot 10 in the valve in the usual way. When thus operating the device a downward pressure is exerted on the extension 6, the air pressure within the cup 1 tends to bulge the walls of the cupv outward in the direction indicated by the dotted lines 13` y shown in Fig. 2.

The` invention also applies to the type of cup in which there 1s no opening between the inner part of the body 1, and the upper parts of the device.

The ribs 2 strengthen the cup against bending outwardly or ina radial direction, but the parts 14 of the wall of the cup in the spaces lbetween the ribs permit this wall to stretch in a circumferential direction oro laterally of the ribs.v These ribs stiflen and strengthen the walls of the cup when bending in a direction radially of the cup, while they do not materially interfere with theV circumferential stretch of said walls.

The annular ridge or thickening 5 at the rim of the cup strengthens the lower edge so that the circumferential stretch is mainly above said rim, as is common'in ldevices of this kind.

The wall of the cup is preferably made thinnest at 15, being the part between the` ridge or thickening. 5. and the lower ends of the ribs 2. The device may be made entirely of vulcanized rubber.

Although but one specific embodiment of thisjginvention has been herein shown and described, it will be understood that some of the details of the construction shown lniay be altered or omitted without. departing body and terminating short of said rim, and from the spirit of this invention as defined that portionof the body between the ribs by the following claim. v being thicker than the part below said ribs. I claim: Signed at Chicago this 26th day of July 5 A, force cup of the class described, com- 1912. prising a concaveelastic body, and a plurality of ribs extending downwardly along the inner concave surface of said body and Witnesses: .spaced uniformly apart, said ribs being ta- R. RUMMLER, 10 pered toward the edge or -rim of the concave I EDWIN PHELPs;

GEORGE C. REEVES. 

